Stability of CFL cores in Hybrid Stars

TL;DR

This paper investigates the stability of color-flavor locked (CFL) quark matter cores in hybrid stars using a self-consistent NJL-like model, demonstrating conditions for their stability and the possibility of multiple phase transitions within stellar configurations.

Contribution

It introduces a self-consistent NJL-like model with a vector interaction to analyze CFL core stability and identifies conditions for multiple phase transitions in hybrid stars.

Findings

Stable CFL cores are possible with sufficiently large superconducting gaps.

Hybrid stars can undergo two phase transitions: hadronic to 2SC and 2SC to CFL.

The model predicts stable stellar configurations with complex phase structures.

Abstract

We study the equation state of strongly interacting quark matter within a NJL-like model in which the chiral condensates and the color superconducting gaps are computed self-consistently as a function of the baryon density. A vector interaction term is added to the Lagrangian in order to render the quark matter equation of state stiffer. For the low density hadronic phase we use a relativistic mean field model. The phase transition to quark matter is computed by a Maxwell construction. We show that stable CFL cores in hybrid stars are possible if the superconducting gap is sufficiently large. Moreover we find stable stellar configurations in which two phase transitions occur, a first transition from hadronic matter to 2SC quark matter and a second transition from 2SC quark matter to CFL quark matter.